Two-dimensional Fourier transform Nuclear Magnetic Resonance (NMR) spectroscopy has been applied to determine the structure of conjugates of glutathione and to study enzyme catalyzed rates of exchange. Unidirectional rates have been determined for the phosphoglucose isomerase catalyzed isomerization and anomerization of glucose-6-phosphate and fructose-6-phosphate, for the adenyl kinase exchange of adenosine diphosphate to adenosine triphosphate with creatine to form adenosine diphosphate and creatine phosphate. From these studies mechanisms of the reactions were proposed and it was demonstrated that two-dimensional NMR spectroscopy is capable of monitoring simultaneously all of the pathways in a complex exchanging system.